<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			var json = {
				"name": "mjj",
				"age": 29,
				"width": 500,
				"opacity": 100
			}
			for(var attr in json){
				console.log(attr,json[attr]);
			}
			
		</script>
	</body>
</html>
